ML20196E409

Proposed Tech Specs Re Daily Exercise of MSIVs

ML20196E409
Person / Time
Site:	Oyster Creek
Issue date:	06/21/1988
From:	GENERAL PUBLIC UTILITIES CORP.
To:
Shared Package
ML20196E374	List: ML20196E370 ML20196E380 ML20196E409
References
NUDOCS 8807010615
Download: ML20196E409 (2)

Text

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I. Functional Test of Valves

1. All containment isolation valves specified in Table 3.5.2 shall

be tested for automatic closure by an isolation signal during l each refueling outage. The following valves are required to close in the time specified below

Main steam line isolation valves ~'> 3 sec and e.10 sec.

Isolation condenser isolation valves 2 60 sec.

Cleanup system isolation valves 2 60 sec.

Cleanup auxiliary pumps system isolation valves j60sec.

Shutdown system isolation valves g 60 sec.

2. Each containment isolation valve shown in Table 3.5.2 shall be demonstrated operable prior to returning the valve to service after maintenance, repair or replacement work is performed on the valve or its associated actuator by cycling the valve through at least one complete cycle of full travel and verifying the specified isolating time. Following maintenance, repair or replacement work on the control or power circuit for the valves shown in Table 3.5.2, the affected component shall be tested to assure it will perform its intended function in the circuit.

3. Quarterly, during periods of sustained power operation, each main steam isolation valve shall be closed (one at a time) and its closure time verified to be within the limits of specification 4.5.I.1 above. Such testing shall be conducted with reactor power not greater than 50% of rated power.

4. Reactor Building to Suppression Chamber Vacuum Breakers

a. The reactor building to suppression chamber vacuum breakers and associated instrumentation, including setpoint, shall be checked for proper operation every three-months.

b. During each refueling outage each vacuum breaker shall be tested to determine that the force required to open the vacuum breaker from closed to fully open does not exceed the force specified in Specification 3.5. A.3.a. The air-operated vacuum breaker instrumentation shall be calibrated during each refueling outage.

Change: 7 0YSTER CREEK 4.5-4 Amendment No: 14, 54, 8807010615 880621 PDR ADOCK 05000219 P DCD

Since the main steam line isolation valves are normally in the open position, more frequent testing is specified. Per ASfiE Boiler and Pressure Vessel code, section XI, the quarterly full closure test will ensure operability and provide assurance that the valves maintain the required closing time. The minimum time of 3 seconds is based on the transient analysis of the isolation valve closure that shows the pressure peak 76 psig below the lowest safety valve setting. The maximum time of 10 seconds is based on the value assumed for the main steam line break dose calculations.

Surveillance of the suppression chamber-reactor building vacuum breakers consists of operability checks and leakage tests (conducted as part of the containment leak - tightness tests). These vacuum breakers are normally in the closed position and open only during tests or an accident condition. As a result, a testing frequency of three months for operability is considered justified for this equipment.

Inspections and calibrations are performed during the refueling outages, this frequency being based on equipment quality, experience, and engineering judgment.

The fourteen suppression chamber-drywell vacuum relief valves are designed to open to the full open position (the position that curtain area is equivalent to valve bore) with a force equivalent to a 0.5 psi differential acting on the suppression chamber face of the valve disk.

This opening specification assures that the design limit of 2.0 psid between the drywell and external environment is not exceedeo. Once each refueling outage each valve is tested to assure that it will open fully in response to a force less than that specified. Also it is inspected to assure that it closes freely and operates properly.

The containment design has been examined to establish the allowable bypass area between the drywell and suppression chamber as 10.5 in.2 (expressed as vacuum breaker open area). This is equivalent to one vacuum breaker disk off its seat 0.371 inch; this length corresponds to an angular displacement of 1.25*. A conservative allowance of 0.10 inch has been selected as the maximum permissible valve opening. Valve closure within this limit may be determined by light indication from two independent position detection and indication systems. Either system provides a control room alarm for a non-seated valve.

At the end of each refueling cycle, a leak rate test shall be performed to verify that significant leakage flow paths do not exist between the drywell and suppression chamber. The drywell pressure will be increased by at least 1 psi with respect to the suppression chamber pressure. The pressure transient (if any) will be monitored with a sensitive pressure gauge. If the drywell pressure cannot be increased by 1 psi over the suppression chamber pressure it would be because a significant leakage path exists; in this event the leakage source will be identified and eliminated before power operation is resumed. If the drywell pressure can be increased by 1 psi over the suppression chamber the rate of change of the suppression chamber pressure must not exceed a rate equivalent to the rate of air flow from the drywell OYSTER CREEK 4.5-13 Change: 22,